Multipartite magnon entanglement and collective steering in cavity magnonics

In this paper, we propose a scalable scheme to prepare multipartite entanglement and collective steering of four magnons, which are placed into four separate transmission line resonators. When the four cavity modes are coupled to a common superconducting qubit, the strong coherent coupling between the magnons and qubit can be established through virtual photon exchange. In the dressed picture, it is of interest to explore two types of interaction under different frequency-matching conditions, being responsible for the continuous-variable quadripartite Greenberger-Horne-Zeilinger and cluster entanglement. Furthermore, the generation of collective steering originates from the dissipation channel of Bogoliubov mode rather than from the conventional asymmetry of the system parameters. The multipartite entanglement in this solid-state device may find potential applications in constructing macroscopic quantum networks and the collective steering may be useful in one-sided device-independent quantum secret sharing.